This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Two-photon fluorescent imaging experiments have shown a much larger intracellular anomalous diffusion in CA1 pyramidal neuron dendrites than in cerebellar Purkinje cell dendrites. The most likely explanation at present is a previously undetected, but significant, difference in the structure of the dendritic cytoskeleton between these two neuron types. This hypothesis will be investigated using ultrastructural methods